How do you read, use, and delete variables in Bash?

Read a variable by prefixing $` (`$name); use ${name} braces to mark its boundary; remove it entirely with unset name.

Assignment uses the bare name (name=...), but reading always needs the $` to trigger expansion. The braces in `${name} matter when the variable name would otherwise run into following text — bash greedily grabs as many valid name characters as it can, so $namelolo` looks for a variable called `namelolo`. `${name}lolo draws a clear boundary.

name="World"
echo "Hello $name"      # Hello World
echo "${name}lolo"      # Worldlolo  (braces fix the boundary)
echo "$namelolo"        # (empty — wrong variable!)
unset name              # delete it; $name is now empty

When to use ${var} syntax:

# Problem: variable boundary unclear
echo "$namelolo"         # Looks for $namelolo (empty!)

# Solution: curly braces
echo "${name}lolo"       # Output: Worldlolo

Deleting variables:

unset name
echo "$name"             # Output: (empty)

Check if variable is set:

# Default value if unset
echo "${name:-default}"

# Assign default if unset
name="${name:-default}"

Tip: Always use "$var" (quoted) to prevent word splitting issues.